Field of the Disclosure
The teachings in accordance with exemplary and non-limiting embodiments of this disclosure generally relate generally to a photo detecting sensor having a micro lens array, and more particularly to a photo detecting sensor having a micro lens array configured to balance energy conversion efficiency in an active detecting area for beams adequately incident on a photo detecting sensor regardless of a central area and a non-active area, and to prevent a optical loss in the non-active area.
Discussion of the Related Art
This section provides background information related to the present disclosure which is not necessarily prior art.
A photo detecting sensor is used for a photoelectric conversion process converting an image processing or a displayed image. That is, the photo detecting sensor grasps movement or existence of a subject using a visible light or an infrared. To be more specific, an infrared, a near infrared and a visible light reflected or emitted from a subject is used by an electromagnetic radiation spectrum to discern changes in the subject. The photo detecting sensors may be regularly and repeatedly aligned to be used as an optical array device.
A unit cell of the photo detecting sensor may be comprised of an active detecting area configured to substantially detect a light incident from outside and a non-active area configured to process a signal detected by the active detecting area. An SNR (Signal to Noise Ratio) and accuracy of light detection can be increased as a received light amount grows greater in a photo detecting sensor. Although it may suffice to increase a transmission light amount (intensity) as much as an amount desired to be improved, an increase of transmission light amount may suffer from restraints due to eye safety, costs and limits on a system, in order to improve the received light amount.
Furthermore, the photo detecting sensor is limited in current resistance characteristics and allowable light energy density in each position in an active detecting area relative to incident light. Thus, the energy conversion efficiency in the photo detecting sensor is mutually different between a central area and a non-active area. For example, although a light incident on the central area has a relatively great optical power, an optical energy density may be saturated due to the light being concentrated in small-sized spots.
Meanwhile, a light incident on a non-active area may have a greater-sized spots due to being of relatively great influence in aberration over the active detecting area to disadvantageously generate an optical loss due to only a part of spots being incident on the active detecting area.